Wireless communication systems or networks such as, for example, cellular telephone communication systems, are commonplace. Some recent developments in connection with wireless communication systems or networks have focused on the use of packet-switched networks, instead of circuit-switched networks, to improve the operation of the wireless communication networks. In general, the use of packet-switched networks enables the development of more complex call routing techniques that may improve call quality and/or that may improve the operating efficiency of the wireless communication network. Wireless communication network quality and efficiency improvements are particularly important due to the rapidly growing volume of wireless subscribers, the increasing complexity and numbers of services being provided and applications being performed via wireless communication networks, and changing international standards. In fact, many of the recently developed switched-packet based wireless communication networks are specifically adapted to support third generation mobile telecommunications systems such as, for example, systems based on CDMA2000 technology, universal mobile telecommunications systems (UMTS) technology, etc.
Wireless communication networks that are based on packet-switched networks typically include a plurality of radio access networks (RANs), each of which is a packet-switched network and each of which is communicatively coupled to one or more base transceiver stations (BTSs). Mobile termination devices or mobile stations such as, for example, cellular phones, send radio frequency signals to and receive radio frequency signals from one or more BTSs. The BTSs convey information (e.g., voice, data, etc.) carried by the radio frequency signals to one or more RANs. The RANs are similar to base station subsystems, which are typically used within second generation CDMA and GSM wireless communication networks. However, in contrast to base station subsystems, RANs typically communicate with one or more other packet-switched networks that enable the RANs to communicate with each other, with other services or applications, etc. In this manner, mobile termination devices or mobile stations may readily access a wireless communication network to interact with one or more services being provided by the wireless network.
When a mobile termination device or mobile system accesses a wireless communication network and requests a service, a set of resources and path connections such as, for example, control and bearer paths, are established to support the requested service. Of course, depending on the nature of the requested service, one or more control paths and one or more bearer paths may be provided for each session or call. The physical communication paths or connections (i.e., the call configuration) initially established at the time the mobile termination device accesses the communication system may provide minimal or acceptable control latency and bearer path delays. However, movements of the mobile termination device through the area covered by the communication system, as well as the dynamic transmission characteristics of the communication system, may cause the initial communication call configuration to become problematic or unacceptable. For example, as a mobile termination device nears or crosses a boundary between the coverage areas of adjacent RANs, the control and bearer path delays may result in excessive control latency and excessive and/or differential bearer path delays.
Some wireless communication networks or systems use a RAN session client (RSC) to manage and/or optimize the control and bearer path configurations for each call or mobile termination device that is communicatively coupled to the RAN. Typically, the RSC attempts to optimize the communication path or connection configuration for each call or session as the mobile termination device physically moves within the area covered by the RAN. Additionally, wireless communication networks may also enable the physical location of the RSC for a session or call to physically move between RSCs as the mobile termination device associated with the call moves near to or crosses a border between RANs. In this way, the location of the RSC may be changed or handed off to dynamically optimize the call configuration.
Unfortunately, RSC reallocations or handoffs are typically implemented using intrusive techniques such as, for example, CDMA hard handoffs, that break connections along active control and bearer paths associated with a session or call and then establish new communication paths or connections (e.g., new control and bearer paths) for the session or call. Such hard handoffs can substantially reduce call quality and, in a case where the new communication paths or connections have inadequate integrity and/or cannot be established, call quality may be degraded and/or the session or call may be lost or dropped. Thus, there is a need for a method and apparatus for a high integrity handoff of a radio access network session client within a wireless network.